Cyanide disposal method

Jewelry Discussion
1

Was: Bombing recipes?

thank you, Paul,

Is there a simple test to be sure the cyanide is completely
neturalized? Perhaps a drop of something added to a small am ount in
a test tube, that will change color?

Andy

2 
Is there a simple test to be sure the cyanide is completely
neturalized? Perhaps a drop of something added to a small am ount
in a test tube, that will change color?

According to my (rather old) Brepohl, in the context of disposing
cyanide solutions from electro-plating jobs, he recommends the
following proceduRe:

  1. Put the cyanide solution into a plastic bowl

  2. Add a 10…20% ferrous sulfate (FeSO4) solution until color
    changes to rost colored, later chartreuse (greenish-yellow). This is
    potassium ferrocyanide / yellow prussiate of potash - K4Fe(CN)6

  3. Now add a 10% ferric chlorid (FeCl3) until the solution gets
    blue. This is Prussian Blue / Berliner Blau / Turnbull Blue /
    Eisen-hexacyanoferrat(II) - Fe7N18C18

According to the book, this is no longer toxic. And you have definite
colors to know when you are there.